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Wednesday 1 July 2020

The first Boeing 737 Max recertification flight just landed, marking a new milestone for the troubled jet

REUTERS/Jason Redmond

After 15 months on the ground, the Boeing 737 Max on Monday took a major step toward returning to passenger service as the troubled jet completed its first recertification test flight.

A Boeing 737 Max 7, registration N7201S, departed from Seattle’s Boeing Field just before 10 a.m. local time for the milestone flight. Boeing and FAA test pilots and certification officials were on board.

The flight was the first of three, all expected to occur this week, which the FAA will use to determine whether Boeing has fixed the problems with the plane, and whether it can return to normal service.

At publication time, the plane was back in the air following its landing at Grant County International Airport, in Moses Lake, Washington. According to a flight plan, it was set to head back to Boeing Field. It appeared to be undergoing additional tests on the way.

The 737 Max has been grounded since March 2019, following the second of two fatal crashes that killed a combined 346 people. The first crash, Lion Air Flight 610, crashed into the Java Sea off Indonesia in October 2018 after 12 minutes, during which the pilots struggled to control the plane. The crash killed 189 people.

Although questions immediately emerged about a new flight-control system on the 737 Max — the latest iteration of Boeing’s 55-year-old workhorse — the plane largely remained in service, with an emergency Airworthiness Directive issued by Boeing and the FAA warning pilots about possible control issues.

In March 2019, Ethiopian Airlines Flight 302 crashed six minutes after taking off from Addis Ababa, Ethiopia, killing all 157 on board. Within days, the plane type was grounded worldwide. On March 13, 2019, the US became one of the last countries to ground the jet.

Investigators found that both crashes were linked to the automated system, called the maneuvering characteristics augmentation system, or MCAS.

MCAS was designed to compensate for the 737 Max having larger engines than previous 737 generations. The larger engines could cause the plane’s nose to tip upward, leading to a stall — in that situation, MCAS could automatically point the nose down to negate the effect of the engine size.

But the system could be activated by a faulty reading from a single angle-of-attack sensor, without any redundancies or backups. In both crashes the sensors are thought to have failed, sending erroneous data to the flight computer and, without a redundant check in place, triggering the automated system.


Source: David Slotnick | Business Insider

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